Alon Cohen (alon)

Food allergies seem to be on the rise and no one knows exactly why. It is still a small minority of people who have true food allergies, but it is helpful to be informed about them. My recommendation is that if a friend tells you that he or his child has an allergy to a food, take it very seriously, as in some cases food allergies can be life threatening.

What is a food allergy? A food allergy is an immune system response to a protein in a food that the body senses as harmful. When the offending food or protein is eaten, the immune system makes antibodies to “fight it off”. The next time that food is eaten, the antibodies release chemicals which cause allergic symptoms. Those symptoms may include: skin rash, diarrhea, vomiting, tingling sensation in the mouth, swelling of the tongue and throat, drop in blood pressure and in severe cases, loss of consciousness and death. Symptoms may occur in just a few minutes or up to two hours after the offending food is eaten.

Any food can cause allergy, but there are eight foods which are responsible for 90% of all food allergies: milk, egg, peanut, tree nut, fish, shellfish, soy and wheat. A food allergy is different from an “intolerance”; an intolerance is not an immune reaction to a protein. An example is lactose intolerance, where a person is deficient in the enzyme necessary to digest the milk sugar, lactose; when he ingests lactose, he may get cramps, bloating and diarrhea. Another example is celiac disease, where a person cannot digest the gluten, a protein that is in wheat and other grains. The effects of celiac disease are severe, but can be avoided by avoiding ALL sources of gluten (a fairly difficult diet to follow!)

How is a food allergy diagnosed? If you or your child is experiencing any of the above symptoms, which are not explained by illness or another condition, you should consult a physician about allergy testing. The two types of allergy tests which are commonly accepted as reliable and valid are skin tests and blood IgE RAST tests. Both of these tests evaluate the immune system’s response to specific proteins. A skin test is done by placing a drop of a specific ‘allergen’ on the skin and scratching or pricking the skin. If that allergen causes the immune system to react, the test site on the skin will swell (like a bug bite). The IgE RAST test requires a blood test, which is sent to a laboratory, where the amount of IgE antibody to specific foods is measured. Other tests that might be done include IgG antibody testing or cytotoxic testing. These have not been proven to be reliable or valid, are very expensive and not recommended by most of the medical community.

A negative skin or RAST test reliably tells you that you are not allergic to the specific food tested. A positive test is far more difficult to interpret; it means that IgE antibodies to that food are present, and the person might be allergic to that food. Once a positive test is obtained, the person must completely eliminate that food or foods from the diet for 4 weeks to see if the symptoms disappear. After the 4 weeks, if the symptoms have cleared, the foods are added back to the diet, one at a time in a controlled situation. If the symptoms reappear with any specific food, the person is probably allergic to it.

What is the treatment for food allergy? Food allergies are treated by eliminating the offending food from the diet. This requires label reading of any packaged food. One needs to learn all of the different names for the food items that he is allergic to. For example, if someone is allergic to milk he needs to avoid any food that contains: milk, milk solids, buttermilk, casein, whey, or cream. This includes many margarines, processed meats and fish and other foods one might not expect to see milk in. It is not uncommon for children to outgrow food allergies. After a food has been eliminated from the diet for several months to years, the allergy can be ‘challenged’ by adding the food back in a controlled situation. If symptoms were breathing problems or significant illness, a food challenge should be done under medical supervision.

How can I learn more about food allergies? “The Food Allergy Network” (www.foodallergy.org) is a very reliable source of food allergy information. They provide practical educational information to help families successfully deal with food allergies.

If you or your child has food allergies and you are having difficulties knowing what to eat/not to eat, contact Lori Brizee of Central Oregon Pediatric Nutrition Consultants, www.centraloregonnutrition.com

Lori Brizee is a Registered Dietitian and co-owner of Central Oregon Pediatric Nutrition Consultants, she has extensive experience in working with children on weight issues.